I really need this for our cars. The Navigation is one of the most used features on my phone. We have 3 kids that play hockey, and it always makes things so much easier to just say the name of the rink we are trying to find, and it guides us right to rinks all over Minnesota. Google navigation, along with the voice recognition, is one of the biggest reasons I will stick with Android and Google, and refuse to own an iphone.
It would be great to have this so I concentrate more on the road, than having to hold onto the phone and look at it watch the map.